因式分6(x-y)3-4(y-x)2.
6(x-y)3-4(y-x)2
=6(x-y)3-4(x-y)2,
=2(x-y)2[3(x-y)-2],
=2(x-y)2(3x-3y-2).
They didn't watch TV _______ they finished their homework. [ ]
A. when
B. as
C. while
D. until
关于“肾腺瘤”影像,下述哪项不正确()
A.单发或多发实性肿块
B.偶可累及双肾
C.常有钙化
D.瘤体中央可有星状瘢痕
E.瘤内常有出血、坏死